I wasn't able to reproduce the behavior you describe. What I've done to test it was:
- Run a clean copy of winXP
- Installed .NET Framework 2.0
- Created an application with RadTabStrip having one tabItem and an instance of RadButton on the container form.
- Added one TabItem on Form's Load event and one more for each button click.
- Moved Telerik.WinControls.dll, Telerik.WinControls.UI.dll and TelerikCommon.dll to my application.
- When I run it there is no error message and everything work as it is expected.
Could you please send me the sample project which is demonstrating the fault behavior of RadTabStrip?
I'm looking forward to your reply.
the Telerik team